Fierce competition in the enameled wire industry using existing technology left thin profits for the manufacturers. To save cost, there is no other way out except energy economy. Some manufacturers of enameled wires developed energy-efficient micro-wire oven for enameling machine, the catalytic combustion chamber of which, as part of the waste-gas recovery and utilization device, is situated on the baking side of the oven chamber. The solvent on the enameled wire is evaporated and combusted inside the said combustion chamber, producing hot air which pre-heats and pushes the fresh air downward into the oven chamber. As a result, the energy-saving effect is not obvious.
Numerous manufacturers have therefore made technological reformation to current equipment successively and a number of patents have been filed. For instance, the Chinese utility model numbered 02290021.7 disclosed a technical solution titled “Energy-efficient Micro-wire Oven for Enameling Machine”. This technical solution involves an energy-saving micro-wire oven which consists of an oven chamber and a waste-gas recovery and utilization device. Further, the waste-gas recovery and utilization device has its inlet installed close to the evaporation area of the oven chamber, and its outlet connected to the baking area of the oven chamber via the circulating fan and the air distribution pipe.
Although this solution pushes the hot air generated during waste-gas recovery process backward into the inner chamber of the oven, due to the long distance between the single inlet and the evaporation area of the oven chamber, tubular heater is still necessary inside the oven chamber for heating purpose. This prevents the realization of optimal energy-saving effect.
Moreover, this solution is applicable only to model of small processing capacity. If several enameled wires are processed side by side on the same machine simultaneously, this structure will become unserviceable.
Another example, Chinese utility model number 03263874.4 discloses a technical solution named “Dual-circulating Horizontal Oven for Enameled Machine” which still fails to achieve the rationalized allocation of heat energy within the whole oven chamber, though the hot air derived from waste-gas recovery process have been pushed into the chamber at both the evaporation and baking areas. In other words, the middle area of the oven chamber is not supplied with heat energy and thus requires heating by tubular heaters.
In addition, this proposal does not take into full consideration the quality of the enameled wire. Because the enameled wire is most vulnerable to pollution by particles at the evaporation area inside the oven chamber when the solvents are evaporated, it is important while utilizing the circulating hot air to consider the amount of utilized hot air compared to fresh hot air, as well as its areas of coverage.
Besides, this proposal provides no solution to the problem of lower emission standard.